Stability Studies on Dry Swabs and Wet Mailed Swabs for Detection of Chlamydia trachomatis and Neisseria gonorrhoeae in Aptima Assays | Journal of Clinical Microbiology

DOI: 10.1128/JCM.02235-16

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FIG 1
Seeded samples for mailed transport. *, four C. trachomatis (CT) and 4 N. gonorrhoeae (GC) strains seeded with low (L), medium (M), and high (H) titers (each strain had a dry and wet state), total of 48 samples. **, five combinations of C. trachomatis/N. gonorrhoeae, two seeded with a C. trachomatis high/N. gonorrhoeae low titer, two with a C. trachomatis low/N. gonorrhoeae high titer, and one with a C. trachomatis low/N. gonorrhoeae low titer (each had a dry and wet state), total of 10 samples. ***, five controls (negative for C. trachomatis and N. gonorrhoeae) containing PBS (each had a dry and wet state), total of 10 samples.
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FIG 2
Transit time for mailers.

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TABLE 1

Stability of dry versus wet swabs seeded with C. trachomatis antigens determined by Aptima CT test

Storage condition/sample^a	Storage temp (°C)	RLU at day:
Storage condition/sample^a	Storage temp (°C)	0	7	14	21	28	56	63	69	77	84
Wet^b
50	4	9,328	8,843	8,999	8,440	5,848	5,707	5,171	4,502	4,498	5,557
	23	9,271	8,426	9,177	8,499	5,382	5,432	5,481	4,715	4,418	5,378
	36	9,098	8,810	8,911	8,416	5,315	5,550	5,166	4,806	4,287	5,576
486	4	9,337	8,888	8,848	8,252	5,509	5,751	5,287	4,286	4,479	5,429
	23	9,196	8,502	9,165	8,441	5,448	5,637	5,679	4,759	4,352	5,332
	36	8,929	8,823	9,332	8,332	5,270	5,475	5,318	4,761	4,329	5,494
39	4	9,675	8,846	8,787	8,422	5,451	5,716	5,367	4,758	4,367	5,499
	23	9,412	8,902	9,568	8,308	5,644	5,623	5,363	4,782	4,450	5,315
	36	9,169	8,449	9,273	8,297	5,565	5,629	5,400	4,750	4,354	5,200
Neg	4	1	1	1	1	1	ND^d	0	1	0	0
	23	1	1	1	1	1	1	ND	1	0	0
	36	1	1	1	1	1	1	1	1	0	1
Dry^c
50	4	9,005	8,842	8,653	8,524	5,453	5,649	5,671	4,889	4,338	5,401
	23	9,429	8,877	8,897	8,338	5,458	5,389	5,264	4,594	4,367	5,395
	36	9,364	8,474	8,584	8,275	5,704	5,644	5,432	4,647	4,463	5,671
486	4	9,231	9,148	8,740	8,678	5,631	5,470	5,511	4,804	4,242	5,322
	23	9,292	8,672	9,069	8,135	5,430	5,311	5,177	4,663	4,384	5,628
	36	9,309	8,339	9,013	8,568	5,468	5,644	5,432	4,647	4,463	5,671
39	4	9,243	8,373	8,734	8,455	5,423	5,496	5,514	4,779	4,377	5,357
	23	9,264	9,031	8,413	8,369	ND	5,704	5,080	4,718	4,466	5,332
	36	ND	8,422	9,057	8,618	5,539	5,580	5,425	4,546	4,482	5,491
Neg	4	1	1	1	1	1	1	1	1	0	0
	23	1	1	1	ND	1	1	1	1	0	1
	36	1	1	1	1	1	1	1	1	0	1

↵a C. trachomatis isolates (isolates 50, 486, and 39) and negative (Neg) sample (phosphate-buffered saline).
↵b Dacron swabs spiked with 50 μl of sample and placed into Aptima transport tubes.
↵c Dacron swabs spiked with 50 μl of sample and stored dry (without medium).
↵d ND, not done.

TABLE 2

Aptima Combo 2 results for all mailed samples tested at the three sites

Inoculum	No. positive/total no.
Inoculum	C. trachomatis	N. gonorrhoeae
C. trachomatis low	77/80
C. trachomatis medium	80/80
C. trachomatis high	80/80
N. gonorrhoeae low		79/80
N. gonorrhoeae medium		79/80
N. gonorrhoeae high		80/80
C. trachomatis low/N. gonorrhoeae low	20/20	16^a/20
C. trachomatis high/N. gonorrhoeae low	40/40	31^b/40
C. trachomatis low/N. gonorrhoeae high	40/40	40/40
Negative	7^c/100	0/100

↵a Four false-negative results are from 2 different samples.
↵b Nine false-negative results are from 5 different samples.
↵c Seven false-positive results are from 4 different samples.

TABLE 3
Temperature ranges recorded in mailers
Temp (°C) % of samples mailed from lab:
UCSF UAB JHU
Over 40^a 2 0 0
30–40^a 80 52 29
2–30 17 48 70
0–2 0 0 0
Below 0 0 0 0
↵a Beyond package insert specifications.

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KEYWORDS

bacteriological techniques

Chlamydia Infections

Chlamydia trachomatis

Neisseria gonorrhoeae

Specimen Handling

Chlamydia trachomatis

Neisseria gonorrhoeae

nucleic acid amplification test

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